Questions tagged [statistics]

Collecting and analyzing numerical data or making numerical summaries of data.

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4
votes
3answers
7k views

Iterate through multiple Raster files and compute statistics using Zonal Statistics

I have a large number of raster images. What I'd like to do is to compute statistics on different sections of these raster files using a polygon. I think everyone is suggesting Zonal statistics. ...
14
votes
5answers
24k views

How to calculate raster statistics for polygons?

how can I calculate sums, averages etc of raster-points (multi-band) per polygon of a vector-layer. I was told that this is called "zonal statistics". I tried that with QGIS first. There is a way to ...
13
votes
2answers
17k views

Getting tabular statistics from table using QGIS?

Are there QGIS tools that will allow users to get tabular statistics from their table? I kind of expected I would be able to just open the table, select the field I was interested in, right-click on ...
8
votes
1answer
5k views

Calculating area weighted average of attribute in one layer by shape in another using ArcGIS for Desktop?

For a project I am working on I would like to intersect fire station response districts with income data to determine the median income per response district. However the borders of the layers ...
5
votes
2answers
890 views

Retrieving LiDAR metrics from relative vertical layers of point cloud?

I need to obtain the proportion of all returns within 5 equally spaced height bins between the cutoff (1 meter) and the maximum height value. I need to get this proportion of all returns for 1000 ...
24
votes
3answers
4k views

Major bug in ArcGIS Zonal statistics?

Update: The bug has been fixed in the ArcGIS 10.4 release I am using ArcGIS 10.2.2 to determine zonal statistics for a number of zones. If there is any NoData in the value raster, I want the zone ...
13
votes
2answers
8k views

How to get GDAL to create statistics for GTiff in Python

I regularly create my own GeoTIFF rasters with GDAL in Python, e.g.: from osgeo import gdal from numpy import random data = random.uniform(0, 10, (300, 200)) driver = gdal.GetDriverByName('GTiff') ds ...
16
votes
7answers
9k views

Get Raster Values from a Polygon Overlay in Opensource GIS Solutions

I have two layers. A polygon-shape-layer with many tiles and a raster-layer containing CORINE 2006 land cover with many categories in a colourmap. I want to obtain for each polygon in the shapelayer a ...
1
vote
1answer
369 views

Statistics on [FID] from table window

Try to do this and you'll get an error message. However you can easily get statistics on [FID] using Summary Statistics tool. Somebody has a good explanation of this? Also note that from within the ...
7
votes
4answers
7k views

Is there a zonal statistics tool to calculate median and mode raster values for each polygon?

I'd like to calculate zonal statistics for a raster where the zones are defined by polygons in a vector layer within QGIS. Specifically I'm interested in calculating the median and mode raster values ...
6
votes
1answer
3k views

Calculating Percentiles in ArcMap?

I have a large polygon dataset (26,000) records with numerous attributes columns. I wish to calculate the percentile rank of each attribute. Say I have population_density in an attribute, is there a ...
14
votes
2answers
5k views

How to calculate average slope in a grid?

This is actually a two part question: Which methods are there to calculate average slope by unit (say km²) for a given area? Are there any special requirements on the data - like additional ...
1
vote
2answers
214 views

Determining Min - Max within zip code (statistics by area)?

I'm new to ArcGIS Desktop. I have created a layer representing zip codes and overlayed it with a layer containing some data points. I want to find the min and max value of the data points in each zip ...
7
votes
2answers
5k views

GDAL does not ignore NoData value

I am trying to calcualate the statistics of a TIFF. The script should ignore the NoData value, but doesn't. What causes this? import gdal from gdalconst import * # register all of the drivers gdal....
7
votes
3answers
13k views

How to count occurrences of one field grouped by values of another?

Is there a way of calculating the number of unique text strings in a field in ArcGIS 10.1? I have a number of repeated strings in this field, but would like to calculate the number of unique strings ...
7
votes
1answer
2k views

Explaining different Standard Deviation results from same data in ArcGIS Desktop and MS Excel?

I have done some interpolation in Geostatistical Analyst in ArcGIS and I got the Standard Deviation (SD) a bit different from the SD that I calculated in Excel Spreadsheet. What algorithm does each ...
5
votes
2answers
2k views

Retrieving average building height in urban areas?

I am looking for a way to collect data on the height profile of some cities over time. I don't need to produce a detailed 3D reconstruction of cities, nor do I need to detect and measure individual ...
3
votes
2answers
4k views

min and max values are not correctly calculated for DEM

I'm working with DEM in QGIS and need to know the min and max values of my data. In the Properties window, under the Metadata tab, the statistics section shows such values. However, I usually find ...
5
votes
1answer
118 views

Calculating Statistics Based on Expression in QGIS?

Is it possible to calculate the sum of polygon areas based on whether or not it has a value in another column? For example: In column 2 I have the area of polygons. I want to calculate the area of ...
3
votes
1answer
373 views

Table of statistics of rasters input in QGIS

I work with QGIS GDAL,I have many raster image 'geotiff' with one band for many dates, I want to create a table that contains statistics for all rasters that I have. I tried the algorithm 'raster ...
10
votes
1answer
4k views

Calculating spatial correlation between features from two separate layers in QGIS

I am trying to determine whether the presence of large numbers of active duty military troops in an area is spatially correlated with higher/lower levels of violent crime. That is, are the areas ...
9
votes
5answers
8k views

How to sum up pixel values in QGIS?

I need to know the value of the sum of all pixels in a raster. However, in the Statistics section of the Metadata tab in Properties, under Sum of All Cells it always indicates 0.00. I have tried with ...
7
votes
2answers
5k views

Frequency, summarize tool options of ArcGIS for Desktop?

I'm looking for some general frequency, summarize tool. What I basically want is some tool like the summarize tool in ArcGIS (right click in the attribute table> summarize) that runs on all attributes ...
5
votes
2answers
337 views

Different models, different contours: are they comparable?

I will get contour lines of electromagnetic field strength around power lines. The contours will be calculated by different agencies using different models. We need to check whether the resulting ...
4
votes
1answer
2k views

How to use/interpret/visualise a distance matrix with unknown coordinates?

How would you go about using a distance matrix where points have no coordinates, i.e. what useful statistics can be made and how to visualise it in some useful way?
2
votes
1answer
4k views

How to call processing toolbox in Qgis' python console

I have been trying to use processing toolbox via python console in Qgis 2.0.1. I am able to write the following comamnds: I am particularly interested to run 'r.statistics' from GRASS module. My ...
7
votes
3answers
1k views

Is it possible to calculate statistics across multiple fields in arcpy?

The summary statistics command can be used in arcpy to calculate statistics - this tool runs against a single field, eg: SUM—Adds the total value for the specified field. Is there an out-of-the-...
6
votes
1answer
3k views

ArcGIS median value from layer?

I've been hunting around ArcGIS 9.3 and having no success at finding a tool/function that can give me the median (not the mean/avg) tabular value of a spatial database. For example, if I have a data ...
3
votes
1answer
2k views

Finding Median, Max and Min values from Raster Layers in QGIS

I currently have 10 years worth of January raster datasets (working on just one month at the moment) of cloud fraction cover from MODIS, and am trying to create new 3 separate rasters which will give ...
3
votes
1answer
3k views

Deriving Z-score values for given field using ArcGIS for Desktop?

I have a shapefile with an attribute field with a range of numerical values. How do I derive z-score values for this field using ArcGIS for Desktop?
2
votes
1answer
225 views

Image Collection Statistics in Google Earth Engine?

How can I extarct mean of each image collection in google earth engine? for example for this code: var modis = ee.ImageCollection("MODIS/006/MOD13Q1") .filterBounds(geometry) .filterDate("2000-01-01",...
2
votes
3answers
246 views

How to show statistically significant incident locations

First let me preface with I tried to search for this solution first but I don't really know how to word it and could not find any results so excuse me if this is a duplicate. I would like to know how ...
1
vote
1answer
825 views

Running regression in each sample separately? [closed]

I'd like to smooth an NDVI image by regression analysis; response of time series NDVI image to Julian date to represent the seasonal changes in NDVI as a function of Julian day. The time series NDVI ...
6
votes
2answers
3k views

how to get max and min from a raster using arcpy?

I have a land surface temperature raster file and I want the max and min of it. minLSTresult = arcpy.GetRasterProperties_management(raster_result, "MINIMUM") minLST = minLSTresult.getOutput(0) ...
6
votes
1answer
3k views

Is it possible to access ArcGIS's table operations “Summarize…” and “Statistics…” in python?

ArcGIS has a few nifty table tools, including Summarize and Statistics. Is there a way to access them through arcpy, or will I have to hack my own methods via math and lists?
5
votes
1answer
2k views

How to create a x-y scatterplot from attributes in QGIS 2.0?

There are a few old packages that allow the creation of x-y scatter plots from attributes in vector data (Scattergram for 1.7) http://plugins.qgis.org/plugins/scattergrammidentify/ (SPQR for very ...
5
votes
1answer
5k views

Recording frequency of names in the attribute table?

I have a question with ArcGIS 9.2. In an attribute table the column [name] includes the name of every place in this layer. Next to that (in columns [numbers]) there should be recorded how often a ...
3
votes
4answers
493 views

Populating polygon with most frequent point attribute using QGIS?

What I have is two features, a polygon showing wards, and a point shapefile showing properties which has an attribute detailing the type of consumer within the household, such as country living, urban ...
3
votes
2answers
870 views

Generating DEMs from point clouds and differencing them?

I have two point clouds obtained via structure from motion (ground photos of sand-dunes + Visual SfM/Agisoft Photoscan). If I wanted to generate a DEM from these point clouds and difference them to ...
2
votes
1answer
5k views

Calculating raster statistics for each band in QGIS?

i need to calculate raster statistics for RGBN (4 channels, multiband image) rasters in QGIS. In Arcgis if you use "calculate statistics" in ArcCatalog, statistics are calculated for every image ...
2
votes
1answer
63 views

An equivalent for field statistics for records

I know how to obtain various statistics for a field, or "column", in an attribute table in ArcGIS. Is there any way to obtain a Mode figure for records, or the "rows" in a table? For instance, an ...
2
votes
1answer
1k views

How to calculate the number of points with differing characteristic in a polygon in ArcMap?

I have a .csv (exported to .shp) database with about two thousand entries of points. One column in this database has certain values (e.g. a point can be 'ash tree', 'beech tree', 'elm tree', etc). I ...
1
vote
2answers
2k views

Calculate raster statistics per polygon in a polygon feature class

I have a raster layer representing land cover which has three categories of pixels: natural, semi-transformed and transformed. I have a polygon feature class where each polygon delineates a ...
1
vote
1answer
72 views

ArcPy SummarizeWithin not availabe in ArcMap with Advanced license?

When running "arcpy.SummarizeWithin_analysis()" in PyCharm, I get an error saying the module isn't available. I've done "import arcpy" and I have ArcGIS Desktop 10.6 Advanced. It also doesn't show up ...
1
vote
2answers
103 views

Getting statistics in cross sections at varying heights in LAS files?

I am looking to cross section my forest at varying heights. I have high return LAS data (8 points/m2 and average point spacing of 0.2m) and I am looking to do more than the simple 1, 2, 3 approach of ...
1
vote
0answers
264 views

mclmcrrt78.dll error while calculating statistics for transects of shorelines [closed]

For analyzing the rate of change of shoreline over the period of 20 years, I installed DSAS version 4 extension to ArcGIS 10.4. While calculating the statistics, the DSAStool calculated the intersect ...
1
vote
1answer
269 views

Calculate the frequency of classes of neighbouring raster cells

I'm struggling with a problem when working with a raster dataset of biotope types: For each cell I would like to find out the frequency of classes in the adjacent cells, e.g. from the 8 neighbouring ...
1
vote
1answer
244 views

Proof low deviations in DEM compared to point dataset

I am not sure how to achieve the following consistently: I have a regular distributed point dataset (surface elevations). From this I derived several DEM using QGIS IDW Interpolation method. Now I ...
1
vote
1answer
487 views

QGIS create point data attribute as the name of the polygon it falls in

I'm working in QGIS with a point data set overlaying a farm with 140 fields. While I can analyse the points from each field individually, I would rather use an awk script to calculate statistics I ...
1
vote
1answer
1k views

How do I Calculate Grouped Percentiles or Batch percentiles in ArcMap?

My question is similar to this one which was answered successfully: Calculating Percentiles in ArcMap? My addition is how do I batch this solution for multiple files or apply a group-by feature to ...